A car is purchased for $20, 000. Its value depreciates by 15% each year. Considering x equals the number of years, which equation can be used to find the number of years it would take the car to be worth $12,000?

Answer options:
1. 20,000(x)^0.85 = 12,000
2. 20,000 - 15x = 12,000
3. 15x - 20,000 = 12,000
4. 20,000(0.85)^x = 12,000